function whichTransitionEvent(el){
var t;
var transitions = {
'transition':'transitionend',
'OTransition':'oTransitionEnd',
'MozTransition':'transitionend',
'WebkitTransition':'webkitTransitionEnd'
}
for(t in transitions){
if( el.style[t] !== undefined ){
return transitions[t];
}
}
}
var transitionEnd = whichTransitionEvent(element);
element.addEventListener(transitionEnd, function(event) {
if(element.className.indexOf('star-expand') === -1) {
element.className += ' star-expand';
}
});